Airbag and belt-tightener units are important passenger-restraining means for protecting motor vehicle passengers in the event of an accident involving a frontal or side impact. Signals from sensor devices are used for deciding when to release the airbag or belt-tightener unit. Acceleration sensor devices, in particular, are fitted centrally in the airbag controller or non-centrally at another point in the vehicle. Central is deemed here to refer in particular to the position in the housing of an airbag controller which is usually fitted under the central console in the motor vehicle. Consequently, any fitting of a control or sensor device outside the airbag controller is referred to as non-central or external. Non-central sensor devices are therefore often referred to as airbag satellites or simply as satellites.
It is important in the case of acceleration sensor devices, in particular, to achieve a mechanically highly rigid coupling of the airbag satellite with the vehicle body. If this does not exist, the mechanical transfer function between satellite and vehicle body changes, and the satellite transmits in part falsified signals. For mounting external airbag controllers, in the main metallic mounting plates, on which the satellites are rigidly fastened by means of screws and counter screws, are fitted in the motor vehicle.
The sensor signals are evaluated in the airbag satellites themselves or in the central airbag controller by algorithms which have to be adapted for each vehicle type. The computational results of the algorithms are from time to time very different for different mounting locations. Especially in the case of acceleration sensor devices, it is therefore particularly important to mount the airbag satellites reproducibly at the same point on the vehicle body, since only in this way can the same evaluation of an impact event be guaranteed for all the vehicles in a vehicle line. Special mounting aids and mounting procedures which prevent any incorrect positioning of an airbag satellite are therefore used in production in the automotive industry.
FIGS. 5a and 5b show a known mounting aid in the form of a mounting cover 3 which is placed on a housing 1 of an airbag satellite. FIG. 5a shows the airbag satellite before installation in the motor vehicle. In this arrangement, the fastening screws 4 cannot be tightened, as the mounting cover prevents access with a mounting tool. Only in the installation position intended for that purpose, as shown in FIG. 5b, can the satellite be fastened to a mounting support.
FIGS. 6a and 6b show the same two arrangements of the satellite on a mounting plate 7, viewed from the back.
The two FIGS. 6a and 6b illustrate the known method for mounting an airbag satellite:                The housing 1 is placed on a mounting plate 7 using a positioning aid 8 (FIG. 6a).        The housing 1 of the satellite is then displaced in the direction of the arrow (FIG. 6b).        The satellite is then fastened to the mounting plate 7 through the cooperation of mounting means.        
A disadvantage of this known mounting aid is the two-part formation of housing and the mounting aid, in particular a mounting cover. The use of two separate components in the production of an airbag satellite entails a high additional logistical outlay. This comprises the handling of a greater number of components and an additional process step in which a housing and a mounting cover have to be assembled.